In this instructable, you will learn how to make a digital timer using the old parts of a defective microwave oven. All parts needed in this project can be salvaged from a defective microwave oven. The main thing you need in this project is the microwave oven's timer module.
Step 1: Gather Parts and Tools Needed.
- Old microwave oven timer (salvaged from an old microwave oven)
- AC cord and connector (can be salvaged from the old microwave oven)
- Electrical tape or heat shrink tubing
- Soldering iron and solder
Step 2: Disassembling the Oven
Warning: Do not attempt do this unless you know about electricity and do not work with the appliance plugged to the mains.
The first thing you need to do is to disassemble the microwave oven. First, take off the cover by removing all screws. You will find several screws after disassembling it. Then, find a screw that holds the timer in place. Next, find a way to take off the timer from its place. You can disconnect or cut some wires if needed. Cut and salvage the wires that supply power to the timer module and disconnect the yellow and black wires from the door switch.
Sorry for the lack of pictures because I needed another hand to do it.
Step 3: Desoldering
Desolder the relays on the board but if you are making an appliance timer, do not desolder it. There are three relays in my board and I desoldered all because I needed the relays for another project. I think you can just leave one relay if you are making the appliance timer.
Step 4: Wiring
Use the salvaged AC connector to power the digital timer module. Strip its ends and tin its tips.
Short the yellow and black wires of the switch so the timer will think that the door is closed.
Connect the power cord to the connector by soldering. After soldering put some heat shrink tubes.
Tip: Slide the heat shrink tubes in before soldering.
Step 5: Testing
Test the timer if it works by connecting the AC connector to the board and then plug it in the wall.
See if there is a display. Don't just leave it bare as I did. You should put an enclosure for your project. Find a way to have an enclosure.
Congratulations! Now you made your own digital timer. You could now use it in the kitchen for timing something.
Thank you for reading! Please comment :)